/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.hadoop.hive.ql.exec;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hive.ql.metadata.HiveException;
import org.apache.hadoop.hive.ql.plan.ExprNodeConstantDesc;
import org.apache.hadoop.hive.serde2.objectinspector.ConstantObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;

/**
 * ExprNodeConstantEvaluator.
 *
 */
public class ExprNodeConstantEvaluator extends ExprNodeEvaluator<ExprNodeConstantDesc> {

  transient ConstantObjectInspector writableObjectInspector;

  public ExprNodeConstantEvaluator(ExprNodeConstantDesc expr) {
    this(expr, null);
  }

  public ExprNodeConstantEvaluator(ExprNodeConstantDesc expr, Configuration conf) {
    super(expr, conf);
    writableObjectInspector = expr.getWritableObjectInspector();
  }

  @Override
  public ObjectInspector initialize(ObjectInspector rowInspector) throws HiveException {
    return writableObjectInspector;
  }

  @Override
  protected Object _evaluate(Object row, int version) throws HiveException {
    return writableObjectInspector.getWritableConstantValue();
  }

}
